A nickel-metal hydride battery usually incorporates an anode comprising a metal-hydride active material and a cathode comprising nickel hydroxide. The anode and cathode are immersed in an electrolyte (such as an aqueous potassium hydroxide solution) and Separated by a porous separator. Stanford R. Ovshinsky and co-workers significantly improved the nickel-metal hydride battery by incorporating disordered (amorphous) metal-hydride active materials into the anode, see U.S. Pat. No. 4,623,597, herein fully incorporated by reference. Ovshinsky and co-workers continued to improve the nickel-metal hydride battery. For example, Ovshinsky and co-workers improved the capacity and peak power of the nickel-metal hydride battery by pressing powdered metal-hydride active materials into porous metal substrates to form the anode and by pressing or pasting powdered nickel hydroxide into porous metal substrates to form the cathode, see U.S. Pat. Nos. 5,856,047 and 6,416,903, herein fully incorporated by reference.
Frank E. Towsley invented a porous cellular metal structure made, for example, by electrodepositing a metal in the interstitial spaces of a compacted bed of polystyrene particles followed by dissolution of the polystyrene, see U.S. Pat. No. 4,053,371, herein fully incorporated by reference. Towsley used such a porous cellular metal, for example, in an improved electrolytic cell, see U.S. Pat. No. 4,121,992, herein fully incorporated by reference, and Towsley suggested a number of other applications such as a filtration membrane, an electrode assembly for batteries, lightweight structural members, impact energy absorbers, and abrasive grinding combinations, see U.S. Pat. No. 4,053,371.
Despite the significant improvements made to nickel-metal hydride batteries, there is a continuing need to increase the capacity and/or peak power characteristics of nickel-metal hydride batteries.